Date of Award

2020

Document Type

Thesis

Degree Name

M.A.

Department

Geography

First Advisor

J. Michael Daniels

Second Advisor

Mike Kerwin

Third Advisor

Donald Sullivan

Keywords

Rock glacier development, Colorado, Schmidt hammer exposure dating

Abstract

Rock glaciers are common landform features found in deglaciated alpine areas. They are commonly used in the study of climatic changes throughout the Holocene and the reconstruction of neoglacial chronologies. For this research, Schmidt hammer rebound values, weathering rind thicknesses, and the length of lichen thalli diameters found on rock glacier surfaces are used to investigate their effectiveness as field-based relative age determination techniques. Additionally, the ability to identify periods of neoglacial activity using these methods is assessed in two neighboring cirque basins in the San Juan Mountains of Colorado. 41 field sites across three rock glaciers are established with approximately 2,050 Schmidt hammer measurements and 300 weathering rind thicknesses collected in total. The Schmidt hammer proved to be the most effective of the three relative age indicators in distinguishing between surfaces of different relative age. The R-values collected indicate three periods of neoglacial activity, which aligns with the neoglacial history of the area. Values derived by the Schmidt hammer in combination with morphological analysis conducted using Google Earth Pro and ArcGIS are then used to model how each rock glacier may have developed over time. This research demonstrates that Schmidt hammer exposure dating is an efficient and robust field method for determining the relative ages of rock glaciers in the San Juan Mountains.

Publication Statement

Copyright is held by the author. User is responsible for all copyright compliance.

Provenance

Received from ProQuest

Rights holder

Brandon K. Bailey

File size

69 p.

File format

application/pdf

Language

en

Discipline

Physical geography

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